• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.420-420
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• 2023

하천의 유량 자료는 하천 관리에 필수적인 요소로, 지속적인 유량측정을 위해 국가 유량 측정망을 구성하여 주요 지점을 대상으로 유량 측정을 수행하고 있다. 측정된 유량자료는 일반적으로 수위-유량 관계곡선식을 개발하여 제공되고 있으며, 홍수파와 배수 영향 등으로 인해 수위-유량 관계곡선식에서 발생하는 산포로 인한 신뢰도에 문제가 우려되는 경우에는 실시간의 정확한 유량자료를 제공하기 위해 H-ADCP를 설치하여 지표유속법 기반의 실시간 유량 자료 생산하여 제공하고 있다. 그러나 H-ADCP를 이용한 유량 측정 방법은 장비의 한계로 인해 상대적으로 규모가 작고 수심이 얕은 하천에 적용하기 어려운 문제가 있다. 따라서, 최근에는 자동유량관측소 지점 확대를 위해 비접촉식 유속계를 활용한 자동유량관측소 운영이 점차 고려되고 있다. 이에 따라 비접촉식유속계를 이용한 유량 측정 결과의 검증 및 유지 관리를 위한 소프트웨어가 필요하다. 이에 본 연구에서는 비접촉식유속계 중 전자파를 이용하여 수표면의 표면유속을 측정할 수 있는 장비인 RQ-30의 측정결과를 분석하기 위해 Microsoft Visual Studio(C#) 사용하여 측정결과의 검토 및 자료 관리를 위한 후처리 소프트웨어를 개발하였다. 개발한 소프트웨어는 측정 원시자료를 읽고, 도시하여 측정 결과를 확인할 수 있으며, 머신러닝 기반의 알고리즘을 적용하여 수위 및 유속 시계열 자료에서 발생하는 이상치를 탐색할 수 있도록 개발하였다. 그리고 탐지된 이상치에 대한 보정을 위해 선형보간, LOESS, SuperSmoother를 사용하여 이상치를 보정하여 결과를 도출할 수 있도록 개발하였다. 추후 본 연구를 통해 개발된 프로그램을 활용하여 측정 자료의 유지 관리 효율성을 증대시킬 수 있을 것으로 기대되며, 지속적인 프로그램의 개선을 통해서 실무적으로 활용이 가능할 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.489-489
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• 2023

최근 유량 측정을 위해 사용되는 ADCP를 통해 부가적으로 측정되는 초음파산란도 자료를 활용하여 부유사농도를 측정하는 연구가 수행되고 있다. 이에 국내에서는 국가하천에 설치되어 있는 자동유량관측소의 초음파산란도를 활용하여 연속적인 부유사농도를 측정하는 연구가 수행되고 있다. 이를 통해 10분 단위로 연속적인 유사량 자료를 생산할 수 있을 것으로 기대되며, 현재 유사량 측정결과의 제공을 위해 사용되는 유량-유사량 관계곡선의 산포로 인한 신뢰도 문제를 개선할 수 있을 것으로 기대되고 있다. 그러나, 이미 설치된 자동유량관측소의 H-ADCP 원시데이터를 활용하여 다지점에서 부유사농도를 측정에 대한 분석을 수행하기 위해서는 초음파산란도의 보정, 관계식 개발, 관계식 적용을 통한 유사량 측정 결과의 분석을 위한 소프트웨어 개발이 필요하다. 이에 본 연구에서는 초음파산란도 자료를 이용하여 부유사농도를 분석할 수 있는 소프트웨어 개발하고자 하였다. 개발된 소프트웨어는 Microsoft Visual Studio를 이용하여 C# 언어를 사용하여 개발하였으며, ComponentOne 라이브러리를 활용하여 그래픽 사용자 인터페이스(GUI)를 구현하였다. 소프트웨어의 구성은 H-ADCP 원시자료와 실측 부유사농도 자료와의 시간동기화를 통해 동일시간에서 측정된 자료를 획득, 초음파산란도의 보정과 지표로 활용할 초음파산란도의 측정영역 분석, 초음파산란도-부유사농도와의 다중 회귀를 통한 관계식 개발 및 통계 분석결과 도출, 관계식을 활용한 부유사농도 계산을 수행할 수 있도록 구성하였다. 본 연구를 통해 개발된 소프트웨어를 통해 추후에 시범적용 예정인 자동유량관측소의 초음파산란도를 활용 부유사농도 측정 방법에 대한 분석 효율성을 향상시키고, 지속적인 개선을 통해서 실제 실무에서 활용이 가능할 것으로 기대된다.

• Korean Journal of Environment and Ecology
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• v.31 no.6
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• pp.485-491
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• 2017

This study examined the germination characteristics by collecting fruits and pretreatment of the diaspore from April 2014 to June 2015 to investigate the diaspore characteristics, seed dispersion, and seed germination characteristics of two myrmecochorous spring ephemerals (MCSE): -Jeffersonia dubia (Jb) and Corydalis remota (Cr)-. The diaspore of Jb was about 5mm-long yellow-dark brown, oblong seeds with the attached amorphous white elaiosome. The mean weights of diaspore, seed, and elaiosome were 15.86mg, 13.46mg, and 2.40mg, respectively, and the elaiosome ratio was 15.13%. The diaspore of Cr was about 1.2mm diameter and glossy black ovoid seeds with the attached white spatula-shaped elaiosome. The mean weights of diaspore, seed, and elaisome were 2.58mg, 2.05mg, and 0.53mg, respectively, and the elaiosome ratio was 20.54%. Camponotus niponensis and Formica japonica transported the diaspore of Jb while Formica japonica and Lasius japonicus transported the diaspore of Cr. The germination percentage of Jb seeds was statistically significant and had the significance level of 1% with the pretreatment and date of sowing. However, it was independent of attachment of elaiosome. The mean germination percentages of Jb seeds was 65.0% during sowing on June 20, 17.5% during sowing on August 19, and 0% during sowing on October 20. The germination percentage of Cr was statistically significant and had the significance level of 5% and 1% with the attachment of elaisome and date of sowing, respectively. The mean germination rates were 54.17% and 35.0% in the non-treatment section and the treatment section with elaisome detached, respectively. The mean germination percentages of Cr seeds was 75.0% during sowing on June 20, 53.75% during sowing on August 19, and 5.0% during sowing on October 20. Considering the fact that the ants transported the diaspores to the ant house when the fruits of MCSE were ripened and dropped the seeds, the direct seeding right after collecting may be most suitable to the characteristics of the evolution of these plant species and may be the best method to obtain the highest germination percentages. Since the ants distribute their seeds, the MCSE produces and attaches the elaiosome to the seed to maintain the symbiotic relationship with ants. The ants then transport the seed to the ant house where the environment is controlled for suitable temperature and humidity, and then the MCSE succeeds in germination after the embryo grows sufficiently in the next spring.

• Journal of Korea Water Resources Association
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• v.47 no.4
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• pp.397-409
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• 2014

In this study, the assessment scheme has been developed to evaluate the ecological function of rivers which were changed by the river improvement project. The evaluating factors are composed of physical structure in river channels and ecological connectivity in river areas, and each value of the factors is quantified based on 4 and 2 variables, respectably. This scheme was applied to past (1918, before artificial river improvement) and present Mankyung River area. A GIS model was adopted for calculating, analysing, and presenting river ecological conditions using the 204 grids and 7 reaches in study area. Comparison results show that the evaluation grade was decreased in both factors after river improvement. The main causes of lower grade (from II to IV) for physical structure are the river straightening and crossing structures. The reduction (from II to III) in ecological connectivity grade effected by linear fragmentation due to roads and rails is found to be greater than areal fragmentation due to land-use. In particular, it is also found that a high degree of ecological connectivity in 1918 was distributed along the river, but that one in 2007 showed a tendency to scatter because of the construction of levee and increase of urbanized area.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.77-83
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• 1983

Effects of rice straw application (particularly application method; surface placement and deep placement) on the biological nitrogen fixing activity of paddy fields and on the growth of rice plant have been investigated by the lysimeter experiment with Aragawa alluvial soil and Tochigi ando soil. 1. Nitrogen fixing activity of plow layer (0~1cm) was increased by the rice straw application, notably by the phototrophs, both deep placement and surface placement, between 1 and 2 months of initial growth stage of rice plant. 2. Surface placement method stimulated the nitrogen fixing activity more significantly them the deep placement method, and also showed good effects on the growth of rice plant. 3. The increased of effect on the nitrogen fixing activity of surface placed area was found to be originated from the applied rice straw and its neigh bouring area. 4. Nitrogen fixing activity of surface placed rice straw was rather promoted by the application of herbicides (2, 4, 6-arichlorophenyl ether) than the non-applicated plot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.671-678
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• 2021

In a previous study, technology protection levels were set on a qualitative basis. That study lacked quantitative standards, so here, we conduct a study to complement the previous study and to present an objective standard. This paper provides a method of setting a technical protection level that applies statistical analysis. To set the technology protection level, statistical analysis of six technical survey items is performed first. Second, the technical survey items are analyzed by AHP to quantify the opinions of experts in order to derive weights for each technical survey item. Finally, by using the normal distribution scatter map and median calculation method, the technology protection level is selected in three stages using the final detailed factor technology score reflecting the weight. The technology protection level methodology developed through this study is the first methodology with objectivity that can evaluate defense technology by level. If this methodology is applied in practice, it is believed that it will provide a scientific and quantitative technology value judgment criterion when setting the technology protection level in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.5
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• pp.365-373
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• 2013

Tile caching technology is a commonly used method that optimizes the delivery of map imagery across the internet in modern WebGIS systems. However the poor performance of the map tile cache update is one of the major causes that hamper the wider use of this technique for datasets with frequent updates. In this paper, we introduce a new algorithm, namely, Partial Area Cache Update (PACU) that significantly minimizes redundant update of map tiles where the update frequency of source map data is very large. The performance of our algorithm is verified with the cadastral map data of Pyeongtaek of Gyeonggi Province, where approximately 3,100 changes occur in a day among the 331,594 parcels. The experiment results show that the performance of the PACU algorithm is 6.6 times faster than the ESRI ArcGIS SERVER$^{(r)}$. This algorithm significantly contributes in solving the frequent update problem and enable Web Map Tile Services for data that requires frequent update.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.961-968
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• 1998

In order to investigate the effects of substrate bias voltage on the formation of$ZnS-SiO_2$ protective film in phase change optical disk by R.F. magnetron sputtering method, thin dielectric film was formed on Si wafer and Corning glass by using ZnS(80mol%)-$SiO_2$(20mol%)t arget under argon gas. In this study, the Taguchi experimental method was applied in order to obtain optimum conditions with reduced number of experiments and to control numerous variables effectively. At the same time this method can assure the reproducibility of experiments. Optimum conditions for film formation obtained by above method were target RF power of 200 W. substrate RF power of 20 W, Ar pressure of 5 mTorr. sputtering time of 20 min.. respectively. The phase of specimen was determined by using XRD and TEM. The compositional analysis of specimen was performed by XPS test. In order to measure the thermal resistivity of deposited specimen, annealing test was carried out at $300^{\circ}C$ and $600^{\circ}C$. For the account of void fraction in thin film, the Bruggeman EMA(Effective Medium Approximation) method was applied using the optical data obtained by Spectroscopic Ellipsometry. According to the results of this work, the existence of strong interaction between bias voltage and sputtering time was confirmed for refractive index value. According to XRD and TEM analysis of specimen, the film structure formed in bias voltage resulted in more refined structures than that formed without bias voltage. But excess bias voltage resulted in grain growth in thin film. It was confirmed that the application of optimum bias voltage increased film density by reduction of void fraction of about 3.7%.

• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.343-351
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• 2015

We introduce how to fit random effects models via a SRC-Stat statistical package. This package has been developed to fit double hierarchical generalized linear models where mean and dispersion parameters for the variance of random effects and residual variance (overdispersion) can be modeled as random-effect models. The estimates of fixed effects, random effects and variances are calculated by a hierarchical likelihood method. We illustrate the use of our package with practical data-sets.

• Journal of Korea Water Resources Association
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• v.35 no.6
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• pp.715-727
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• 2002

The travel time of a flood through a river reach can be estimated by dividing the river length by the mean velocity with which the flood passes downstream. It is closely related to storage constant for the watershed routing of a flood. There are so many empirical formulas available for the estimation of travel time but the results computed generally show great different depending on individual formulas. In the present study, the mean velocity data computed in the process of water surface profile computation for a probability flood through more than 100 different river reaches were collected along with the mean river bed slope of each river reach. And then, a regression analysis is made between the mean river bed slope and the mean velocity, which showed a wide scatter along the mean regression curve, which appears to be due to the different in the magnitude of probability rainfall and size of watershed area. Therefore, methods have been developed to remove the effect of these factors and generalized empirical equation is proposed to relate the mean velocity to mean river bed slope of a reach. Hence, if the mean river bed slope of a river reach is estimated from the longitudinal river profile, the mean velocity can be computed by the generalized equation along with the probability rainfall and watershed area of the river reach under consideration, which leads to the estimation of travel time through a river reach.